The present invention relates generally to data communication and more particularly to establishing a wireless data communication link between the data bus of a vehicle and a remote interrogation device.
Many of today""s vehicles are equipped with sophisticated computer systems. These computer systems typically include a central computer that receives data from sensors located throughout the vehicle. The sensors record data information concerning systems of the vehicle, and the central computer system uses this information to control the operation of the vehicle, store the data for historical purposes, and/or analyze the data for diagnostic purposes. For example, many vehicles include central computer systems that receive data from sensors such as throttle sensors, oxygen sensors, and fuel flow sensors to regulate the engine.
In addition to providing data for operation of the vehicle, many vehicle computer systems include sensors that provide data concerning the various systems of the vehicle for use in diagnostic and maintenance operations. For example, many heavy duty vehicles now include sensors that provide data relating to safety systems, such as the status of the brakes of the vehicle. Additionally, many systems provide logistics data relating to the vehicle, such as mileage, fuel tank levels, gas mileage, status of contents hauled in the vehicle, etc.
To access data from the computer system, many of today""s vehicles include electrical pin-out connectors that are accessible for connection. In these systems, a diagnostic device may be connected to the pin-out connector to receive and transmit data to and from the onboard computer of the vehicle. In light of this, several interrogation devices have been developed in the past few years that interface with the pin-out connector of a vehicle and transmit and receive data relating to the operation of the vehicle and status of its various systems. Although these conventional systems are effective for receiving data from and transmitting data to the data bus of the vehicle, these interrogation devices require physical connection to the vehicle, which may not be desirable in situations where the vehicle is either in transit or is remote from the interrogation device requesting data input.
Although remote, wireless communication with the computer system of a vehicle is typically desired, the physical limitations of the communication infrastructure of most vehicles hinder the move to wireless communication. For instance, the communication systems of many conventional vehicles, such as heavy duty vehicles (e.g., tractor-trailer vehicles) use a communication protocol that requires real-time communication with the vehicle. Specifically, many heavy duty vehicles include a data bus that is operated using one of two bus standards, either J1708 or J1939. Communication on the data bus of these vehicles may be problematic due to the nature of the J1708 and J1939 standards. For example, a data bus that uses the J1708 standard is a differentially driven, twisted pair. The data bus of this system is half duplexed such that data transmitted on the data bus is transmitted on both of the twisted pair of wires, where data transmitted on one of the twisted pair of wires is mirrored with respect to the other twisted pair wire. Because data transmitted on the bus is transmitted on both wires of the bus, the data bus does not have a transmit and receive line. Further, systems attempting to transmit data on the data bus must monitor the data bus for an idle state when data is not transmitted, before the system transmits data on the data bus.
As discussed, many conventional interrogation devices have been developed for use in direct electrical communication with the data bus of a vehicle. These systems, to some extent, do not experience problems with the infrastructure or protocol of the data bus, because they are in direct electrical connection with the data bus. This direct electrical connection allows these systems to monitor the idle states of the data bus in real-time. For this reason, in the past few years several interrogation devices have been developed for transmitting and receiving data from the data bus of a vehicle using direct electrical communication with the data bus. Importantly, these interrogation devices typically use software programs that are specifically designed to interface with the data bus in real-time. The software programs monitor the bus for idle states and transmit data to the bus.
Due to the limitations of direct physical connection with the vehicle, however, there has been a desire to retrofit these existing systems with front end wireless communication add-on systems such that the existing interrogation devices may be remotely located away from the vehicle. For instance, many of these systems are now retrofitted with RF based communication systems that communicate with the vehicle remotely. Although these conventional systems provide wireless communication, the retrofit of an existing interrogation device may be costly.
Specifically, because these retrofitted systems communicate with the vehicle remotely, instead of a direct electrical connection, there is some delay due to processing of the data and transmission of the data. Because of these delays, most of these systems can no longer provide a real-time data link with the data bus of the vehicle. Instead, most retrofitted systems use data buffers that buffer data transmitted to and data received from the data bus of the vehicle. The buffered data is held until the data bus has an idle state, at which time the data is applied to the data bus. This buffering of data presents a problem, however, with retrofitting existing interrogation devices.
Specifically, most of these interrogation systems, prior to retrofit, have computer software designed for real-time communication with the data bus. As such, as part of the retrofit process, the original software for operating the interrogation system must be updated or otherwise reprogrammed to accommodate for the delay due to buffering of data. The reprogramming or updating of these programs can be costly. For instance, third party contractors, who may no longer be available for updating the software, may have created many of the programs. Further, the software may have been written using older software programming languages. In some instances, the software may have to be totally reprogrammed. As such, solutions are needed that allow for remote, wireless communication with the data bus of vehicles that is either real-time or approximately real-time, such that the software of the interrogation device and the data bus communicate in approximate real-time and the software of the interrogation device does not have to be altered.
One problem with providing remote, approximate real-time data communication is the data bus infrastructure and protocol and the data communication devices themselves. This data bus infrastructure and protocol is one reason existing systems buffer data. With reference to FIG. 1, some of the problems associated with wireless communication with the data bus of a vehicle are illustrated. Specifically, FIG. 1 shows a transceiver 10 for transmitting to and receiving data from a remote location to be applied to the data bus of a vehicle. The transceiver includes both a transmitter 12 and a receiver 14 connected to the data bus 16 of a vehicle. In this illustration, the data bus uses J1708 protocol and is a differentially driven, twisted pair. As discussed previously, the data bus does not include a read and write data communication line. Instead, both the transmitter and the receiver of the transceiver are commonly connected to the bus at a node 17. This common connection causes problems when data is transmitted from the receiver of the transceiver to the data bus.
Specifically, when the receiver 14 of the transceiver receives data 18, the data 18 is applied to the data bus 16. Because of the common connection at the node 17, the data 18 is also applied to the transmitter line of the transmitter 12. As such, as data is applied to the data bus, it is also transmitted by the transceiver. This is first problematic because the data transmitted by the transceiver, which is referred to herein as either looped or false data 19, is transmitted to a remote interrogation device and is basically bad data. Secondly, as the transmitter 12 transmits the data, the receiver 14 of the transceiver also receives the false data 19. Left unchecked, this looped or false data 19 will potentially corrupt not only the remote interrogation device but also the data bus.
Because of the infrastructure and protocol of the data bus and problems associated with transceivers receiving what they transmit, these problems must be addressed as part of signal processing when data is transmitted to and received from a remote location in a wireless format. Because of this data processing problem, many conventional add on wireless systems buffer the data, because they cannot process the data without significant delays. As discussed, however, buffering of the data in many instances requires reconfiguring existing software of interrogation devices, which can be costly. As such, communication systems are needed that alleviate the problems with looped or false data without requiring added delay, such that data may be transmitted to and from the data bus of the vehicle in an approximate real-time manner.
In addition to problems associated with the delays in remote, wireless data communication with the data bus of a vehicle, there are also particular problems associated with the limited transmitting and receiving range of most transceivers. As discussed, some vehicles, such as heavy duty vehicles, use data bus infrastructures and protocol that require interrogation devices to wait for an idle state on the bus prior to transmitting information to the data bus. A problem is presented when a transceiver is connected to the data bus of the vehicle for receiving external signals such as RF or IR signals. Specifically, when not in use for data communication, the transceiver may receive spurious noise signals from various sources that may be input on the data bus as false data and corrupt data on the data bus. For example, in the case of IR transceivers, light from the headlights of other vehicles or sunlight may be received by the transceiver and applied to the data bus as false data. Similarly, in the case of RF transceivers, spurious RF signals from many sources such as radios, cell phones, etc. may received as false data on the data bus. As such, a communication system is needed that isolates the data bus from remote data input when a remote data communication link is not established with the data bus.
An additional problem with wireless, remote data communication may be caused by the transmission and reception ranges of the interrogation devices. For example, in instances in which the interrogation device uses RF communication, there is a limited coverage area within which the interrogation device may receive and transmit data. A similar problem may be experienced in instances where IR communication is used. Specifically, most transceivers have limited transmission and reception ranges, such that vehicles outside the range may receive either intermittent or corrupted data signals. In these instances, it is typically not advantageous to establish a data communication link with a vehicle that is either outside or on the fringe of the transmitting and receiving range of the transceiver.
Problems may also be realized where there are several vehicles in an area with which a remote interrogation device wishes to establish a data communication link. For instance, if the interrogation device is used in a garage or shipyard setting, the user of the interrogation device may wish to communicate with either a particular vehicle or several of the vehicles one at a time. Similarly, in a factory setting, the user of the interrogation device may wish to correspond with vehicles one at a time, as they move past the interrogation device. Problems may occur, however, where two or more of the vehicles attempt to establish a data communication link with the interrogation device at the same time. As such, systems are needed that accommodate for the transmission and reception limitations of the transceivers. Additionally, systems are needed that provide for establishing a data link with one vehicle in an environment where several vehicles are present.
A still further problem is the time required for data communication between the data bus of a vehicle and a remote interrogation device. Specifically, there may be a limited time for transmission of data between the vehicle and the interrogation device, due to the fact that the vehicle may be traveling past the interrogation device or may only be stopped for a brief time period. In these instances, it is advantageous to decrease the time required to transmit data between the data bus and the interrogation device. Further, systems are needed that record data concerning the vehicle during operation and systems that store data for transmission to a vehicle at a later time.
As set forth below, the apparatus, methods, and computer program products of the present invention may overcome many of the deficiencies identified with wireless data communication between remote interrogation devices and the data bus of vehicles. In particular, the present invention provides several apparatus, methods, and computer program products that establish a data communication link between a remote interrogation device and the data bus of a vehicle with reduced transmission delay. Due to this reduced transmission delay, modifications to the existing software of the interrogation device may not be necessary. As such, remote, wireless interrogation devices may be designed or retrofitted in a cost affective manner. Additionally, the present invention provides apparatus and methods that isolate the data bus of a vehicle from the transceiver used for remote, wireless communication when a data communication link is not established, such that false data, such as spurious signals, are not applied to the data bus.
Further, the present invention provides apparatus and methods that facilitate data communication with a vehicle, when the vehicle is located within the transmission and reception range of the interrogation device. Also, the present invention provides apparatus and methods that can facilitate the establishment of a data communication link with one vehicle in environments where several vehicles are within the transmission and reception area of the interrogation device.
Additionally, the present invention provides apparatus and methods that can increase the amount of data transmitted between the data bus of a vehicle and a remote interrogation device during a given data link time. Also, the present invention can store data related to the vehicle during the operation of the vehicle for later transmittal to a remote interrogation device or store data at a remote interrogation device for later transmittal to the data bus of a vehicle.
As discussed above, one problem with conventional, retrofit, interrogation devices is the need to update or reprogram the existing software to accommodate for delays associated with wireless transmission of data. To remedy problems associated with wireless data transmission delays, the present invention provides an apparatus for validating data transmitted to and data transmitted from a data bus, such that receipt of looped or false data either by the data bus or the remote location is eliminated. Further, the present invention analyzes the data bit by bit such that the data is transmitted in a wireless format with minimal delay.
The apparatus of this embodiment includes a local transceiver in operable electrical communication with the data bus of the vehicle. This local transceiver is used to transmit data from the data bus to a remote location and receive data transmitted to the data bus from a remote location. Connected to the local transceiver is a local processor that analyzes data either transmitted to or received from the data bus.
In operation, the local processor analyzes data received by the local processor one bit at a time to decrease delay in data processing. Additionally, the local processor analyzes the data received by the local processor and prevents propagation of looped or false data from being transmitted to either the data bus or to the remote location. As such, the apparatus of the present invention allows for wireless data communication with minimal delay, while also alleviating problems associated with receipt of looped or false data that is received by the local processor when data is transmitted to either the data bus or a remote location.
In one embodiment, the local processor of the present invention decreases the delay for transmission of data by monitoring the edge of each bit. Specifically, the local processor of this embodiment determines the value of each bit of the data by sensing a transition in logic states in the data, such that the local processor processes the data with minimal delay.
In addition to providing an apparatus and method for establishing a data link having minimum delay between a data bus of a vehicle and a remote interrogation device, the present invention also provides computer program products. Specifically, the present invention provides a computer readable storage medium having computer readable program code means embodied in the storage medium. The computer-readable program code means include first computer-readable program code means for analyzing data transmitted to and from the data bus one bit at a time, such that data may be transmitted to and from the data bus with minimal delay. The computer-readable program code means also includes a second computer-readable program code means for preventing propagation of looped or false data to the remote location when data is transmitted to the data bus and propagation of false data to the data bus when data is transmitted from the data bus to the remote location.
In addition to providing apparatus, methods, computer program products that validate with minimal delay data transmitted to and from the data bus of a vehicle, the present invention also provides apparatus and methods for establishing a data communication link between a data bus of a vehicle and a remote interrogation device, where false data due to signal noise may otherwise be received by the data bus and corrupt data on the data bus. The apparatus of this embodiment includes a local transceiver in operable electrical communication with the data bus of a vehicle for transmitting data to and transmitting data from the data bus. Connected to both the local transceiver and the data bus is a local processor. The apparatus of this embodiment also includes a switch in operable electrical communication with the local processor, local transceiver, and the data bus. The switch has a closed position in which it connects the local transceiver and the data bus and an open position in which it isolates the local transceiver from the data bus.
In operation, when a data link is to be established between the data bus of a vehicle and a remote interrogation device, the processor closes the switch, such that the data bus may receive data transmitted to the vehicle via the local transceiver. Importantly, in instances in which data is not transmitted to the data bus of the vehicle, the local processor opens the switch to thereby isolate the data bus from the transceiver. As such, the apparatus of the present invention allows for remote data communication with the data bus of the vehicle, while also allowing the data bus to be isolated from receipt of false data due to outside noise signals, when the data bus is not receiving external data signals to thereby alleviate corruption of existing data on the data bus.
As discussed above, the present invention provides an apparatus and method for isolating the data bus from false data due to external noise when the data bus is not receiving external data. In some embodiments of the present invention, it is advantageous to alert the local processor that a remote interrogation device is attempting to form a data communication link with the data bus of the vehicle, such that the processor will close the switch connecting the data bus to the local transceiver. In this embodiment of the present invention, the apparatus further includes a remote interrogation device having a remote transceiver in electrical communication with a remote processor for transmitting data to and receiving data from the data bus of the vehicle.
In operation, in a data transfer mode in which the remote interrogation device attempts to establish a data communication link with the data bus of the vehicle, the remote processor transmits a data link command to the local processor. Upon receipt of the data link command, the local processor closes the switch to thereby establish a data communication link between the data bus of the vehicle and the remote processor of the interrogation device.
As discussed previously, in some embodiments, the remote transceiver may have a limited transmission and reception range, outside of which vehicles may receive either corrupted or intermittent data signals. In these instances, it may be advantageous to delay connection of the data bus with the local transceiver until the vehicle is within the transmission and reception range of the interrogation device.
In this embodiment of the present invention, the apparatus further includes a counter in electrical communication with the local processor for counting the number of times the data link command is transmitted by the remote processor of the interrogation device. In this embodiment, the remote processor sequentially transmits a plurality of data link commands to the local processor. The counter counts the number of times the data link command is received by the local processor, and the local processor compares the counts indicated by the counter to a predetermined threshold value. When the counts indicated by the counter equals the threshold value, the local processor closes the switch to thereby create a data communication link between the remote processor and the data bus of the vehicle.
In another embodiment of the present invention, the remote processor sequentially transmits a data link command at predetermined time intervals to the local processor. The counter counts the number of times the data link command is received by the local processor, and the local processor monitors the time interval between receipt of each data link command. If the processor data link command is not received during the predetermined time interval, the local processor resets the counter. As such, the data link command must be received consecutively a number of times equal to the data link threshold value before the local processor will establish a data communication link with the remote interrogation device.
This embodiment helps to ensure that the vehicle is within the transmission and reception range of the interrogation device before a data communication link is established. Specifically, vehicles either on the fringe or not within the transmission and reception range of the interrogation device are more likely to receive an intermittent or corrupted data link command. By resetting the counter each time a data communication link is not received within the predetermined time interval, the present invention can alleviate the formation of a data communication link with a vehicle either on the fringe or outside the transmission and reception range of the interrogation device.
In a further embodiment, the data link threshold value may have a selected value that is sufficiently large such that vehicles located outside or on the fringe of the data transmission and reception range of the remote transceiver of the interrogation device are more likely to not establish a data communication link with the interrogation device. Specifically, in this embodiment, the local processor of the vehicle may only intermittently receive the periodic data link command transmitted by the remote processor due to the vehicle""s location outside or on the fringe of the transmission and reception range of the interrogation device. As such, the local processor of the vehicle will reset the counter each time a data link command is missed. If the data link threshold value is set sufficiently large, the vehicle will most likely not receive the data link command enough times consecutively to exceed the individual data link threshold value associated with the vehicle.
In addition to providing an indication to the local processor that a remote interrogation device is attempting to form a data link with the data bus of the vehicle, in some embodiments it may be advantageous to alert both the local and remote processors that a data communication is established and also to alert the local and remote processors when a data communication link has ended. In this embodiment of the present invention, in the data transfer mode, both the local and remote processors periodically transmit a heartbeat signal to each other indicating an established data communication link between the remote processor and the data bus. In this embodiment, the local and remote processors monitor a time interval between receipt of the periodic heartbeat signals, and if the heartbeat signal is not received within a predetermined time interval, the local or remote processor determines that the data communication link is no longer viable. At this point, if the local processor determines that the data communication link is no longer established, it will open the switch to thereby isolate the data bus from the local transceiver and alleviate the introduction of false data in the form of signal noise into the data bus. If the remote processor no longer receives the heartbeat signal from the local processor, it will cease transmitting data to and attempting to receive data from the data bus of the vehicle.
As discussed previously, there may be instances in which more than one vehicle is in the vicinity of the remote interrogation device, and the user wishes to establish a data communication link with one of the vehicles. As such, one embodiment of the present invention provides an apparatus for establishing a data communication link between a data bus of one of at least two vehicles and an interrogation device having a remote processor and a remote transceiver. In this embodiment of the present invention, the apparatus includes a communication unit located on each of the vehicles. Each of the communication units includes a local transceiver in operable electrical communication with the data bus of the associated vehicle and a local processor in operable electrical communication with both the local transceiver and the data bus.
In operation, the remote processor of the interrogation device controls the remote transceiver to transmit a periodic data link command to the local processor of each of the communication units. Each of the local processors of the communication units receive the periodic data link command and compare the number of times the data link command has been received to a individual data link threshold value that differs for each vehicle. When the number of times the data link command is received equals the individual data link threshold value associated with one of the vehicles, the local processor of the communication unit associated with the vehicle closes its associated switch to form a data communication link between the bus of the vehicle and the remote processor of the interrogation device. As such, a data communication link is formed between the interrogation device and the data bus of the vehicle. After a data communication link has been established with one of the vehicles, the remote processor ceases transmission of the data link command, such that the remaining vehicles will not receive the command and attempt to establish a data link while the remote processor is transmitting data to the first vehicle.
An important aspect of this embodiment of the present invention is that the data link threshold value associated with each vehicle is preferably different from the other vehicles. As such, when the number of times the data link command has been sent equals the data link threshold value associated with one of the vehicles, the present invention will establish a data communication link with that vehicle, as opposed to establishing a data communication link with all vehicles in the transmission and reception range of the interrogation device.
As discussed, in this embodiment of the present invention, each of the vehicles has an individual data link threshold value that is different from the other vehicles. To create the individualized data link threshold values for each vehicle, in one embodiment of the present invention, the communication unit for each vehicle further includes a random number generator in electrical communication with the local processor. In this embodiment of the present invention, the data link threshold value associated with each vehicle is defined by a preset number and a number generated by the random number generator associated with each vehicle.
In operation, the random number generator associated with each vehicle generates a random number that is added to the preset number to create an individual data link threshold value for each vehicle. In this embodiment, similar to the previous embodiment, each of the local processors of each of the communication units receives the periodic data link command and compares the number of times the data link command has been received to the individual data link threshold value associated with the vehicle. When the number of times the data link command is received equals the individual data link threshold value associated with the vehicle, the local processor of the communication unit associated with the vehicle forms a data link between the bus of the vehicle and the remote processor. In one further embodiment of the present invention, the local processors reset the associated counters, if a data link command is missed by the local processor, such that the local processor must receive a consecutive number of data link commands equaling the data link threshold value before a data communication link will be made.
In addition to providing apparatus and methods that establish data communication links between the data bus of a vehicle and a remote interrogation device, the present invention also provides apparatus and methods for storing data related to the vehicle during operation of the vehicle, such that the data may be later transferred to a remote interrogation device. Additionally, the present invention provides apparatus and methods that store data in a remote interrogation device for latter transfer to a vehicle during a data communication link with the vehicle.
In the first of these embodiments, the present invention further includes a local memory device in electrical communication with the local processor. During the operation of the vehicle, the local processor receives data relating to the operating parameters of the vehicle and/or its cargo and stores the data in the local memory device. When the local processor establishes a subsequent data communication link with a remote processor, the stored data in the local memory device can be transmitted to the remote interrogation device for permanent storage and analysis.
In the second of these embodiments, the present invention further includes a remote memory device in electrical communication with the remote processor. In this embodiment of the present invention, the remote memory device includes data to be transmitted to the data bus of a vehicle, such that in a subsequent data communication link with the data bus of the vehicle, the remote processor transmits this data to the vehicle.
An additional aspect of both of these embodiments, is that in some instances the data stored in either the local or remote memory devices may be transmitted by the local and remote processors at a relatively high data transmission rate, as compared to the data speed of the data bus. Specifically, in these embodiments, the data may be transmitted by the local and remote processors and when received by the corresponding system, buffered in the local and remote memory devices prior to application to either the data bus or the remote processor for processing. As such, data information may be transmitted quickly in embodiments where the time interval available for establishing a data communication link is relatively small, such as in the instance in which the vehicle is moving past the interrogation device on a highway.